Eco-friendly, economical, sustainable – First load-bearing prefabricated recycling concrete wall produced
By Bernd Betz, Beton-Betz and Herbert Kahmer, SYSPRO
The German precast producer Beton-Betz has been working for the last 1.5 years in the EU INTERREG project SeRaMCo. The company’s role is mainly to contribute to new raw material compositions and precast elements. Beton-Betz is supported by several universities who research on the characteristics of recycling concrete in their laboratories. During the past months Beton-Betz has gathered practical know-how in using recycled concrete waste.
Crushing technology optimised. Concrete residues from Beton-Betz’s own production have been reused in a special mobile recycling plant with 3 sieves; the sand and grain fractions obtained in this way were stored on the company premises.
Testing is now entering the implementation phase. In autumn 2018, concrete floor slabs made of recycling concrete were produced for the first time and weathered on Beton-Betz’s storage site, as little was known about the effects of their shrinkage. Now, having passed the first winter, no significant differences to normal concrete are being observed.
Application for building permit. The composition found in the trial deviates from currently applied German standards, as crushed fines are used - which is produced in large quantities during recycling and has a very high refinement.
It’s up to the building authority in the city of Tübingen, who has a lot of experience with recycling concrete, to provide the building permit.
A plan for a residential building was submitted there. Exterior and interior walls and floors made of recycling concrete are to be used. The structural dimensioning must prove the usability which means that the modulus of elasticity and creep/shrinkage should be known. For this purpose, Beton-Betz set up two building components In February with the aim to monitor and showcase eventual differences to traditional concrete.
The Tübingen testing office will inspect the endurance test on 29 April and then hopefully approve the first reference project: